Circulating and synovial fluid hyaluronan levels

Objective. To assess the effect of intraarticular (IA) corticosteroid on hyaluronan (HA) concentrations in synovial fluid (SF) and serum and the clearance of ¹³¹I-labeled albumin from the joints of patients with rheumatoid arthritis (RA), osteoarthritis (OA), and ankylosing spondylitis (AS). Methods. SF and serum were collected before and 2 weeks and 2 months after IA steroid injection. The HA concentration was assessed using an enzyme-linked immunosorbent assay and ¹³¹I-albumin clearance from joints was assessed using an external gamma counter. Results. In RA patients, HA concentrations in the SF were increased following IA steroids, while the serum concentrations were decreased. In OA patients, HA concentrations in SF tended to increase initially (decreasing thereafter), and were associated with increased HA concentrations in serum. There were less marked alterations in the AS patients. Albumin clearance rates were decreased significantly (2 weeks postinjection) only in the RA patients. Estimated HA flux revealed discrepancies between the HA concentration and the rate of flux in RA and AS patients. Conclusions. These findings suggest that IA steroid injection is associated with a restoration in the relationship between SF and serum HA concentrations toward normal levels.